/*******************************************************************************
 * Copyright (c) 2012-2015 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ext.java.jdt.text;

import org.eclipse.che.ide.api.editor.text.Region;
import org.eclipse.che.ide.api.editor.text.RegionImpl;
import org.eclipse.che.ide.runtime.Assert;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/** Event describing the change of document partitionings. */
public class DocumentPartitioningChangedEvent {

    /** The document whose partitionings changed */
    private final Document fDocument;

    /** The map of partitionings to changed regions. */
    private final Map<String, Region> fMap = new HashMap<String, Region>();

    /**
     * Creates a new document partitioning changed event for the given document. Initially this event is empty, i.e. does not
     * describe any change.
     *
     * @param document
     *         the changed document
     */
    public DocumentPartitioningChangedEvent(Document document) {
        fDocument = document;
    }

    /**
     * Returns the changed document.
     *
     * @return the changed document
     */
    public Document getDocument() {
        return fDocument;
    }

    /**
     * Returns the changed region of the given partitioning or <code>null</code> if the given partitioning did not change.
     *
     * @param partitioning
     *         the partitioning
     * @return the changed region of the given partitioning or <code>null</code>
     */
    public Region getChangedRegion(String partitioning) {
        return (Region)fMap.get(partitioning);
    }

    /**
     * Returns the set of changed partitionings.
     *
     * @return the set of changed partitionings
     */
    public String[] getChangedPartitionings() {
        String[] partitionings = new String[fMap.size()];
        fMap.keySet().toArray(partitionings);
        return partitionings;
    }

    /**
     * Sets the specified range as changed region for the given partitioning.
     *
     * @param partitioning
     *         the partitioning
     * @param offset
     *         the region offset
     * @param length
     *         the region length
     */
    public void setPartitionChange(String partitioning, int offset, int length) {
        Assert.isNotNull(partitioning);
        fMap.put(partitioning, new RegionImpl(offset, length));
    }

    /**
     * Returns <code>true</code> if the set of changed partitionings is empty, <code>false</code> otherwise.
     *
     * @return <code>true</code> if the set of changed partitionings is empty
     */
    public boolean isEmpty() {
        return fMap.isEmpty();
    }

    /**
     * Returns the coverage of this event. This is the minimal region that contains all changed regions of all changed
     * partitionings.
     *
     * @return the coverage of this event
     */
    public Region getCoverage() {
        if (fMap.isEmpty())
            return new RegionImpl(0, 0);

        int offset = -1;
        int endOffset = -1;
        Iterator<Region> e = fMap.values().iterator();
        while (e.hasNext()) {
            Region r = e.next();

            if (offset < 0 || r.getOffset() < offset)
                offset = r.getOffset();

            int end = r.getOffset() + r.getLength();
            if (end > endOffset)
                endOffset = end;
        }

        return new RegionImpl(offset, endOffset - offset);
    }
}
